Add -mno-shared to x86 assembler
On ELF target, the assembler normally generates code which can go into a shared library where non-weak symbols can be preempted. The -mno-shared option tells the assembler to generate code not for a shared library, where non-weak symbols won't be preempted. The resulting code is slightly smaller. This option mainly affects the handling of branch instructions. gas/ * config/tc-i386.c (no_shared): New. (OPTION_MNO_SHARED): Likewise. (elf_symbol_resolved_in_segment_p): Check no_shared. (md_longopts): Add mno-shared. (md_parse_option): Handle OPTION_MNO_SHARED. (md_show_usage): Add -mno-shared. * doc/c-i386.texi: Document -mno-shared. gas/testsuite/ * gas/i386/i386.exp: Run relax-4 and x86-64-relax-3. * gas/i386/relax-4.d: New file. * gas/i386/x86-64-relax-3.d: Likewise.
This commit is contained in:
H.J. Lu
parent
422349a385
commit
573cc2e57d
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@ -1,3 +1,13 @@
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2015-05-08 H.J. Lu <hongjiu.lu@intel.com>
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* config/tc-i386.c (no_shared): New.
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(OPTION_MNO_SHARED): Likewise.
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(elf_symbol_resolved_in_segment_p): Check no_shared.
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(md_longopts): Add mno-shared.
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(md_parse_option): Handle OPTION_MNO_SHARED.
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(md_show_usage): Add -mno-shared.
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* doc/c-i386.texi: Document -mno-shared.
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2015-05-07 H.J. Lu <hongjiu.lu@intel.com>
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* config/tc-i386.c (elf_symbol_resolved_in_segment_p): New.
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@ -524,6 +524,11 @@ static enum x86_elf_abi x86_elf_abi = I386_ABI;
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static int use_big_obj = 0;
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#endif
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#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
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/* 1 if not generating code for a shared library. */
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static int no_shared = 0;
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#endif
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/* 1 for intel syntax,
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0 if att syntax. */
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static int intel_syntax = 0;
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@ -8785,6 +8790,10 @@ elf_symbol_resolved_in_segment_p (symbolS *fr_symbol)
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/* Symbol may be weak or local. */
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return !S_IS_WEAK (fr_symbol);
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/* Non-weak symbols won't be preempted. */
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if (no_shared)
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return 1;
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/* Global symbols with default visibility in a shared library may be
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preempted by another definition. */
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return ELF_ST_VISIBILITY (S_GET_OTHER (fr_symbol)) != STV_DEFAULT;
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@ -9484,6 +9493,7 @@ const char *md_shortopts = "qn";
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#define OPTION_MBIG_OBJ (OPTION_MD_BASE + 18)
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#define OPTION_OMIT_LOCK_PREFIX (OPTION_MD_BASE + 19)
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#define OPTION_MEVEXRCIG (OPTION_MD_BASE + 20)
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#define OPTION_MNO_SHARED (OPTION_MD_BASE + 21)
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struct option md_longopts[] =
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{
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@ -9494,6 +9504,7 @@ struct option md_longopts[] =
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#endif
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#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
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{"x32", no_argument, NULL, OPTION_X32},
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{"mno-shared", no_argument, NULL, OPTION_MNO_SHARED},
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#endif
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{"divide", no_argument, NULL, OPTION_DIVIDE},
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{"march", required_argument, NULL, OPTION_MARCH},
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@ -9554,6 +9565,10 @@ md_parse_option (int c, char *arg)
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/* -s: On i386 Solaris, this tells the native assembler to use
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.stab instead of .stab.excl. We always use .stab anyhow. */
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break;
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case OPTION_MNO_SHARED:
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no_shared = 1;
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break;
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#endif
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#if (defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) \
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|| defined (TE_PE) || defined (TE_PEP) || defined (OBJ_MACH_O))
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@ -9980,6 +9995,8 @@ md_show_usage (FILE *stream)
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-mold-gcc support old (<= 2.8.1) versions of gcc\n"));
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fprintf (stream, _("\
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-madd-bnd-prefix add BND prefix for all valid branches\n"));
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fprintf (stream, _("\
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-mno-shared enable branch optimization for non shared code\n"));
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# if defined (TE_PE) || defined (TE_PEP)
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fprintf (stream, _("\
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-mbig-obj generate big object files\n"));
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@ -297,6 +297,16 @@ The @code{.att_syntax} and @code{.intel_syntax} directives will take precedent.
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This option forces the assembler to add BND prefix to all branches, even
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if such prefix was not explicitly specified in the source code.
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@cindex @samp{-mno-shared} option, i386
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@cindex @samp{-mno-shared} option, x86-64
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@item -mno-shared
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On ELF target, the assembler normally generates code which can go into a
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shared library where non-weak symbols can be preempted. The
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@samp{-mno-shared} option tells the assembler to generate code not for
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a shared library, where non-weak symbols won't be preempted. The
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resulting code is slightly smaller. This option mainly affects the
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handling of branch instructions.
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@cindex @samp{-mbig-obj} option, x86-64
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@item -mbig-obj
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On x86-64 PE/COFF target this option forces the use of big object file
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@ -1,3 +1,9 @@
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2015-05-08 H.J. Lu <hongjiu.lu@intel.com>
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* gas/i386/i386.exp: Run relax-4 and x86-64-relax-3.
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* gas/i386/relax-4.d: New file.
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* gas/i386/x86-64-relax-3.d: Likewise.
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2015-05-07 H.J. Lu <hongjiu.lu@intel.com>
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* gas/i386/i386.exp: Run relax-3 and x86-64-relax-2.
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@ -396,6 +396,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_32_check]]
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run_dump_test "note"
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run_dump_test "relax-3"
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run_dump_test "relax-4"
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}
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# This is a PE specific test.
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@ -752,6 +753,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
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run_list_test "x86-64-size-inval-1" "-al"
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run_dump_test "x86-64-relax-2"
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run_dump_test "x86-64-relax-3"
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}
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set ASFLAGS "$old_ASFLAGS"
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@ -0,0 +1,32 @@
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#source: relax-3.s
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#as: -mno-shared
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#objdump: -dwr
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.*: +file format .*
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Disassembly of section .text:
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0+ <foo>:
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[ ]*[a-f0-9]+: eb 1c jmp 1e <local>
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[ ]*[a-f0-9]+: eb 16 jmp 1a <hidden_def>
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[ ]*[a-f0-9]+: eb 16 jmp 1c <global_def>
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[ ]*[a-f0-9]+: e9 fc ff ff ff jmp 7 <foo\+0x7> 7: (R_386_PC)?(DISP)?32 weak_def
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[ ]*[a-f0-9]+: e9 fc ff ff ff jmp c <foo\+0xc> c: (R_386_PC)?(DISP)?32 weak_hidden_undef
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[ ]*[a-f0-9]+: e9 fc ff ff ff jmp 11 <foo\+0x11> 11: (R_386_PC)?(DISP)?32 weak_hidden_def
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[ ]*[a-f0-9]+: e9 fc ff ff ff jmp 16 <foo\+0x16> 16: (R_386_PC)?(DISP)?32 hidden_undef
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0+1a <hidden_def>:
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[ ]*[a-f0-9]+: c3 ret
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0+1b <weak_hidden_def>:
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[ ]*[a-f0-9]+: c3 ret
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0+1c <global_def>:
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[ ]*[a-f0-9]+: c3 ret
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0+1d <weak_def>:
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[ ]*[a-f0-9]+: c3 ret
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0+1e <local>:
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[ ]*[a-f0-9]+: c3 ret
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#pass
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@ -0,0 +1,33 @@
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#source: relax-3.s
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#as: -mno-shared
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#objdump: -dwr
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.*: +file format .*
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Disassembly of section .text:
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0+ <foo>:
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[ ]*[a-f0-9]+: eb 1c jmp 1e <local>
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[ ]*[a-f0-9]+: eb 16 jmp 1a <hidden_def>
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[ ]*[a-f0-9]+: eb 16 jmp 1c <global_def>
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[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq b <foo\+0xb> 7: R_X86_64_PC32 weak_def-0x4
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[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq 10 <foo\+0x10> c: R_X86_64_PC32 weak_hidden_undef-0x4
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[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq 15 <foo\+0x15> 11: R_X86_64_PC32 weak_hidden_def-0x4
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[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq 1a <hidden_def> 16: R_X86_64_PC32 hidden_undef-0x4
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0+1a <hidden_def>:
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[ ]*[a-f0-9]+: c3 retq
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0+1b <weak_hidden_def>:
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[ ]*[a-f0-9]+: c3 retq
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0+1c <global_def>:
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[ ]*[a-f0-9]+: c3 retq
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0+1d <weak_def>:
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[ ]*[a-f0-9]+: c3 retq
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0+1e <local>:
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[ ]*[a-f0-9]+: c3 retq
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#pass
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